1. Field of the Invention
This invention is concerned with a head support for a thermal printer.
More specifically, the invention is concerned with an important feature of a thermal printer which is the location of the thermal head on the paper drive roll.
2. Description of Related Art
It is well known that problems can arise if the thermal head and the paper are not properly aligned. In this respect, the drive roll which carries the printing head is required to be aligned with the paper. A problem existing with prior art mechanisms is the accurate alignment of the thermal head on the drive roll.
Consequently, the desired or optimum position for the thermal head is that it is to be maintained in a tangential relationship to the drive roll, otherwise a poor printing quality is produced.
Moreover, printing quality is affected in response to a normal passing for the roll rotation pins or at least in a position near the points determined relative to these ideal lines, and further, considering that each movement away from the optimum or desired disposition is also a factor which affects the printing quality.
Therefore, in order to provide for desired legibility of printed material and to produce a good and possibly excellent quality printing, it was necessary to provide mechanics or mechanical arrangements for supporting the thermal head, and to provide supporting and positioning parts for the drive roll pins so as to make and position the roll pins in an extremely precise arrangement and with tolerances extremely restricted, so as to provide a printer body with high definiteness.
Costs are also a necessary factor to be considered. Therefore, it is necessary to consider the workings, together with this required definiteness, and this results in a raising of or increase in the costs of the resultant end product.
A further problem with which the prior art is concerned is that due to construction inexactnesses in the disposition of the head and in the roll disposition of the printing roll, further inexactnesses in the head and roll dispositions are due to assembling of the parts which may not be proper so that due to accidental causes such as knocks or thermal expansion.
In the prior art, there are known apparatus that provide the support with roll hooking parts for the paper but require a machine construction having exactness, and there are known compression apparatus for compression of the head onto the roll but these apparatus do not compensate for the constructive plays.